/*
 * Copyright (C) 2008 ZXing authors
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package com.wanhe.qrcode;

import android.content.Context;
import android.graphics.PixelFormat;
import android.graphics.Point;
import android.graphics.Rect;
import android.hardware.Camera;
import android.hardware.Camera.CameraInfo;
import android.hardware.Camera.Size;
import android.os.Build;
import android.os.Handler;
import android.view.SurfaceHolder;

import java.io.IOException;


/**
 * This object wraps the Camera service object and expects to be the only one
 * talking to it. The
 * implementation encapsulates the steps needed to take preview-sized images,
 * which are used for
 * both preview and decoding.
 * 
 */
@SuppressWarnings("deprecation")
public final class CameraManager {

	private static int MIN_FRAME_WIDTH = 240;
	private static int MIN_FRAME_HEIGHT = 240;
	private static int MAX_FRAME_WIDTH = 480;
	private static int MAX_FRAME_HEIGHT = 480;

	private final CameraConfigurationManager configManager;
	private Camera camera;
	private Rect framingRect;
	private Rect framingRectInPreview;
	/*** 是否初始化过 **/
	private boolean isInitialized;
	/*** 是否预览中 **/
	private boolean isPreviewing;
	private int requestedFramingRectWidth;
	private int requestedFramingRectHeight;
	/**
	 * Preview frames are delivered here, which we pass on to the registered
	 * handler. Make sure to
	 * clear the handler so it will only receive one message.
	 */
	private final PreviewCallback previewCallback;
	/**
	 * Autofocus callbacks arrive here, and are dispatched to the Handler which
	 * requested them.
	 */
	private final AutoFocusCallback autoFocusCallback;

	static final int SDK_INT; // Later we can use Build.VERSION.SDK_INT
	static {
		int sdkInt;
		try {
			sdkInt = Integer.parseInt(Build.VERSION.SDK);
		} catch (NumberFormatException nfe) {
			// Just to be safe
			sdkInt = 10000;
		}
		SDK_INT = sdkInt;
	}

	public CameraManager(Context context) {
		this.configManager = new CameraConfigurationManager(context);
		previewCallback = new PreviewCallback(configManager);
		autoFocusCallback = new AutoFocusCallback();
	}

	/**
	 * Opens the camera driver and initializes the hardware parameters.
	 * 
	 * @param holder
	 *            The surface object which the camera will draw preview frames
	 *            into.
	 * @throws IOException
	 *             Indicates the camera driver failed to open.
	 */
	public void openDriver(SurfaceHolder holder) throws IOException {
		Camera theCamera = camera;
		if (theCamera == null) {
			theCamera = Camera.open();
			if (theCamera == null) {
				throw new IOException();
			}
			camera = theCamera;
		}
		theCamera.setPreviewDisplay(holder);

		if (QRCodeUtil.hasGingerBread()) {
			CameraInfo info = new CameraInfo();
			Camera.getCameraInfo(0, info);
			if (info.facing == CameraInfo.CAMERA_FACING_BACK) {
				camera.setDisplayOrientation(info.orientation);

			} else {
				camera.setDisplayOrientation(90);
			}
		}

		if (!isInitialized) {
			isInitialized = true;
			configManager.initFromCameraParameters(theCamera);

			if (requestedFramingRectWidth > 0 && requestedFramingRectHeight > 0) {
				setManualFramingRect(requestedFramingRectWidth, requestedFramingRectHeight);
				requestedFramingRectWidth = 0;
				requestedFramingRectHeight = 0;
			}
		}
		configManager.setDesiredCameraParameters(theCamera, false);

	}

	/**
	 * Closes the camera driver if still in use.
	 */
	public void closeDriver() {
		if (camera != null) {
			camera.release();
			camera = null;
			// Make sure to clear these each time we close the camera, so that
			// any scanning rect
			// requested by intent is forgotten.
			framingRect = null;
			framingRectInPreview = null;
		}
	}

	/**
	 * Asks the camera hardware to begin drawing preview frames to the screen.
	 */
	public void startPreview() {
		Camera theCamera = camera;
		if (theCamera != null && !isPreviewing) {
			theCamera.startPreview();
			isPreviewing = true;
		}
	}

	/**
	 * Tells the camera to stop drawing preview frames.
	 */
	public void stopPreview() {
		if (camera != null && isPreviewing) {
			camera.stopPreview();
			previewCallback.setHandler(null, 0);
			autoFocusCallback.setHandler(null, 0);
			isPreviewing = false;
		}
	}

	/**
	 * A single preview frame will be returned to the handler supplied. The data
	 * will arrive as byte[]
	 * in the message.obj field, with width and height encoded as message.arg1
	 * and message.arg2,
	 * respectively.
	 * 
	 * @param handler
	 *            The handler to send the message to.
	 * @param message
	 *            The what field of the message to be sent.
	 */
	public void requestPreviewFrame(Handler handler, int message) {
		Camera theCamera = camera;
		if (theCamera != null && isPreviewing) {
			previewCallback.setHandler(handler, message);
			theCamera.setOneShotPreviewCallback(previewCallback);
		}
	}

	/**
	 * Asks the camera hardware to perform an autofocus.
	 * 
	 * @param handler
	 *            The Handler to notify when the autofocus completes.
	 * @param message
	 *            The message to deliver.
	 */
	@SuppressWarnings("deprecation")
	public void requestAutoFocus(Handler handler, int message) {
		if (camera != null && isPreviewing) {
			autoFocusCallback.setHandler(handler, message);
			try {
				camera.autoFocus(autoFocusCallback);
			} catch (RuntimeException re) {
				re.printStackTrace();
			}
		}
	}

	/**
	 * Calculates the framing rect which the UI should draw to show the user
	 * where to place the
	 * barcode. This target helps with alignment as well as forces the user to
	 * hold the device
	 * far enough away to ensure the image will be in focus.
	 * 
	 * @return The rectangle to draw on screen in window coordinates.
	 */
	public Rect getFramingRect() {
		if (framingRect == null) {
			if (camera == null) {
				return null;
			}
			Point screenResolution = configManager.getScreenResolution();

			if (screenResolution.x <= 854) {
				MIN_FRAME_WIDTH = 240;
				MIN_FRAME_HEIGHT = 240;
				MAX_FRAME_WIDTH = 280;
				MAX_FRAME_HEIGHT = 280;

			} else if (screenResolution.x > 854) {
				MIN_FRAME_WIDTH = 360;
				MIN_FRAME_HEIGHT = 360;
				MAX_FRAME_WIDTH = 580;
				MAX_FRAME_HEIGHT = 580;
			}

			int width = screenResolution.x * 3 / 4;
			if (width < MIN_FRAME_WIDTH) {
				width = MIN_FRAME_WIDTH;

			} else if (width > MAX_FRAME_WIDTH) {
				width = MAX_FRAME_WIDTH;
			}

			int height = screenResolution.y * 3 / 4;
			if (height < MIN_FRAME_HEIGHT) {
				height = MIN_FRAME_HEIGHT;
			} else if (height > MAX_FRAME_HEIGHT) {
				height = MAX_FRAME_HEIGHT;
			}
			int leftOffset = screenResolution.x / 6;
			int topOffset = (screenResolution.y - height) / 2;

			framingRect = new Rect(leftOffset, topOffset, leftOffset + width,
					topOffset + height);

		}

		return framingRect;
	}

	/**
	 * Like {@link #getFramingRect} but coordinates are in terms of the preview
	 * frame,
	 * not UI / screen.
	 */
	public Rect getFramingRectInPreview(Context contex) {
		if (framingRectInPreview == null) {
			Rect framingRect = getFramingRect();
			if (framingRect == null) {
				return null;
			}
			Rect rect = new Rect(framingRect);
			Point cameraResolution = configManager.getCameraResolution();
			Point screenResolution = configManager.getScreenResolution();
			rect.left = rect.left * cameraResolution.x / screenResolution.x;
			rect.right = rect.right * cameraResolution.x / screenResolution.x;
			rect.top = rect.top * cameraResolution.y / screenResolution.y;
			rect.bottom = rect.bottom * cameraResolution.y / screenResolution.y;
			int px = QRCodeUtil.dp2px(contex,30);
			rect.left = rect.left - px;
			rect.top = rect.top - px;
			rect.right = rect.left + rect.width() + px;
			rect.bottom = rect.top + rect.height() + px;

			framingRectInPreview = rect;
		}
		return framingRectInPreview;
	}

	/**
	 * Allows third party apps to specify the scanning rectangle dimensions,
	 * rather than determine
	 * them automatically based on screen resolution.
	 * 
	 * @param width
	 *            The width in pixels to scan.
	 * @param height
	 *            The height in pixels to scan.
	 */
	public void setManualFramingRect(int width, int height) {
		if (isInitialized) {
			Point screenResolution = configManager.getScreenResolution();
			if (width > screenResolution.x) {
				width = screenResolution.x;
			}
			if (height > screenResolution.y) {
				height = screenResolution.y;
			}
			int leftOffset = (screenResolution.x - width) / 2;
			int topOffset = (screenResolution.y - height) / 2;
			framingRect = new Rect(leftOffset, topOffset, leftOffset + width, topOffset + height);
			framingRectInPreview = null;
		} else {
			requestedFramingRectWidth = width;
			requestedFramingRectHeight = height;
		}
	}

	/**
	 * A factory method to build the appropriate LuminanceSource object based on
	 * the format
	 * of the preview buffers, as described by Camera.Parameters.
	 * 
	 * @param data
	 *            A preview frame.
	 * @param width
	 *            The width of the image.
	 * @param height
	 *            The height of the image.
	 * @return A PlanarYUVLuminanceSource instance.
	 */
	public PlanarYUVLuminanceSource buildLuminanceSource(Context contex, byte[] data, int width, int height) {
		Rect rect = getFramingRectInPreview(contex);
		int previewFormat = configManager.getPreviewFormat();
		String previewFormatString = configManager.getPreviewFormatString();
		switch (previewFormat) {
		// This is the standard Android format which all devices are REQUIRED to
		// support.
		// In theory, it's the only one we should ever care about.
		case PixelFormat.YCbCr_420_SP:
			// This format has never been seen in the wild, but is compatible as
			// we only care
			// about the Y channel, so allow it.
		case PixelFormat.YCbCr_422_SP:
			return new PlanarYUVLuminanceSource(data, width, height, rect.left, rect.top,
					rect.width(), rect.height());
		default:
			// The Samsung Moment incorrectly uses this variant instead of the
			// 'sp' version.
			// Fortunately, it too has all the Y data up front, so we can read
			// it.
			if ("yuv420p".equals(previewFormatString)) {
				return new PlanarYUVLuminanceSource(data, width, height, rect.left, rect.top,
						rect.width(), rect.height());
			}
		}
		throw new IllegalArgumentException("Unsupported picture format: " +
				previewFormat + '/' + previewFormatString);
	}

	public Size getPreviewSize() {
		if (null != camera) {
			return camera.getParameters().getPreviewSize();
		}
		return null;
	}

}
